Such a device is connected to a parachute canopy for deploying the parachute canopy out of a container adapted to be closed and opened, typically a harness container.
The parachute canopy is foldable in said container.
In the art, such a pilot chute device typically comprises:
a inflatable, typically soft pilot chute adapted to assist the deployment of the parachute canopy, the inflatable pilot chute being foldable and adapted to be packed into the so-called container,
and spring means adapted to push the inflatable pilot chute outside the container when said container is opened.
U.S. Pat. No. 3,693,917 illustrates a solution of such a pilot chute device, and in U.S. Pat. No. 5,722,619 is disclosed a spring loaded pilot chute; a spring is disposed within the pilot chute structure and said structure is connected by a bridle to the canopy to be deployed.
Below, traversing drawbacks linked to the inertia induced by the weight of the spring means when said spring means is propelled outside the container, into the airstream is expected.
Potential retention, including strangulation, of the bridle which the pilot chute device is attached to is also concerned.
Are further concerned:
ergonomics concerning the disposition of the elements disposed (folded) within the so-called container,
technical control of the security elements by the parachutist,
the possibility of automation of the pilot chute device extraction out of said so-called container.
As a complement to the above-cited drawbacks, it is recommended to traverse what follows, in relation to risks existing with prior art spring loaded pilot chutes: At the terminal free fall velocity, an air depression is created just above the back of the parachutist, when said parachutist is in the standard flat position (horizontal, chest downwardly oriented). The drag involved by the pilot chute device when expelled from the container is then very low. Such an inappropriate situation can even be stressed, for example in case of an AFF (Accelerated Free Fall) jump. As a consequence, if the expelling force created by the detent of the spring, when it springs out of the container, does not exceed the inertia induced by the weight of the spring before the canopy part of the pilot chute gets the relative wind, then the pilot chute device, together with the pilot chute bridle, fall down on the parachutist back, for an undetermined duration of time.
As long as the pilot chute device does not slip, or fall, out of said area of low pressure and recovers a quite high relative wind, the pilot chute device is inactive.
The consequences are as follows:
the parachutist remains in an inappropriate (potentially dangerous) free fall,
the deployment of the canopy which the pilot chute device is connected to be deployed,
potentially the pilot chute bridle can interfere with the pilot chute device; strangulation can occur, the canopy remains undeployed; this is dramatic.